Poly (C.sub.2 -C.sub.4 alkylene terephthalate) such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT) are well known resins for a number of uses including molding applications. Such resins are frequently blended with various additives to improve properties such as impact strength, resistance to warping, flame resistance, and thermal stability. U.S. Pat. Nos. 4,393,153; 4,180,494; 4,096,202; and 4,034,013 describe certain impact modifiers which have been suggested for use with polyalkylene terephthalates. U.S. Pat. Nos. 4,010,219 and 4,101,601 describe certain epoxy compounds which have been suggested for use in imparting improved tensile and melt strength properties to polybutylene terephthalate molding compounds. U.S. Pat. No. 4,195,134 describes a combination of certain impact modifiers and certain diepoxy compounds for use in polyalkylene terephalate molding compositions for improving the hydrolytic stability of such compositions.
The search has continued, however, for polyalkylene terephthalate molding compositions having even further improved impact behavior The present invention was made as a result of such a search.